1. Field of the Invention
The present invention relates to a method and apparatus for isolating and purifying nucleic acid using a single surface, and more particularly, a method of performing cell concentration, cell disruption and DNA purification using a single surface.
2. Description of the Related Art
In general, to extract DNA from a clinical sample, processes of concentrating target cells in a sample, disrupting the concentrated cells, and isolating and/or purifying DNA released from the disrupted cells have to be performed. To perform such processes on a solid support, surfaces having different chemical functional groups suitable for each operation have to be used. However, in general, a surface useful for cell concentration and a surface useful for DNA purification required different functional groups. Therefore, in order to use such surfaces having different functional groups suitable for each operation in a lab-on-a-chip (“LOC”), separate chambers having surfaces appropriate to each operation need to be manufactured, resulting in a complicated system and method of manufacture. In addition, a plurality of pumps and valves are required to flow fluids into each chamber, further complicating the system. Therefore, there is a need for a single surface that can both bind cells in a clinical sample and DNAs released from the sample.
U.S. Pat. No. 6,617,105 discloses a method of isolating nucleic acid from a sample containing cells, the method comprising: binding cells in the sample to a solid support coated with a cell binding moiety; disrupting the isolated cell; binding nucleic acid released from the disrupted cells to the solid support; and recovering the nucleic acid from the solid support. However, in U.S. Pat. No. 6,617,105, chaotropic salts or detergents are used for cell disruption, and a method disclosed in U.S. Pat. No. 5,234,809 is used for nucleic acid purification. U.S. Pat. No. 5,234,809 discloses a process for isolating nucleic acids from a nucleic acid-containing starting material, comprising mixing the starting material, a chaotropic substance and a nucleic acid binding solid phase, separating the solid phase with the nucleic acid bound thereto from the liquid, and washing the solid phase nucleic acid complexes. Therefore, the inventors of the present invention have earnestly studied to solve the problems of the prior art, and found that a single surface comprising a compound having a hydrophobic moiety for cell separation and a pH dependent charge switching moiety for nucleic acid purification permits efficient isolation of cells and subsequent isolation of nucleic acids released from the cells, thus completing the present invention.